Network tool

Subnet splitter

Split an IPv4 or IPv6 CIDR network into smaller child networks. Output is limited to the first 256 child networks.

Parent network: 8.8.8.0/24
IP version: IPv4
Parent prefix: 24
Child prefix: 26
Child networks: 4
Shown networks: 4

8.8.8.0/26 8.8.8.64/26 8.8.8.128/26 8.8.8.192/26

Reference

Output fields

Parent network: The original CIDR block being split into smaller child networks.
Child prefix: The longer prefix length used for each smaller subnet.
Child networks: The ordered subnet list, starting from the first address in the parent block.
Output cap: Large splits are limited to the first 256 child networks to keep the page fast.

Overview

What this tool does

Subnet splitter divides one CIDR network into smaller child networks with a longer prefix length.

Use it when you need to allocate a larger network into smaller ranges for teams, environments, routers, firewall rules, or documentation. Output is capped at 256 child networks so very large splits stay fast.

Examples

Example splits

IPv4 quarters

8.8.8.0/24 into /26 Produces four child networks, each containing 64 IPv4 addresses. Split /24 into /26

IPv6 child prefixes

2001:db8::/32 into /36 Shows the first child networks for a larger IPv6 documentation prefix. Split IPv6 example

Results

How to read results

The parent prefix is the original network size. The child prefix must be larger, which creates smaller networks. The child network list is ordered from the first address in the parent block upward.

Boundaries

Limits

Very large splits are capped at 256 displayed child networks to keep the page responsive. If the result is capped, use a narrower parent network or a less-specific child prefix for a smaller output.

Next steps

CIDR notation explained Review prefix lengths before splitting a network. CIDR prefix cheat sheet Compare common parent and child prefix sizes. CIDR calculator Check the parent network details before splitting. Range to CIDR Convert arbitrary start/end ranges into CIDR blocks.